A Geneticist in Our Future

We FINALLY have an appointment for Makayla to see a geneticist!  For...late November (ugh). 

During my conversation with the geneticist, she explained that it would be very unlikely that Makayla would have Ocular Albinism (OA) because it is something that is typically passed down only from mother's to their sons, and that Makayla is much more likely to have Oculocutaneous Albinism (OCA).

I was a little confused by this, because I had read and understood that Makayla could have OA if my husband and I both carried the recessive gene and that it's only passed from mother to son when the mother carries a dominant gene.  I'm a science nerd with a particular interest in genetics, so I don't typically find myself lost when talking genes, but we agreed that we'll finish this genetics lesson when we meet in Novemeber.  I am so looking forward to it!



*Here's a short blurb from the National Organization of Albinism and Hypopigmentation (NOAH) on the differences between OA and OCA and types of albinism:

Types of Albinism

While most people with albinism have very light skin and hair, not all do. Oculocutaneous (pronounced ock-you-low-kew-TAIN-ee-us) albinism (OCA) involves the eyes, hair and skin. Ocular albinism (OA), which is much less common, involves primarily the eyes, while skin and hair may appear similar or slightly lighter than that of other family members.
Over the years, researchers have used various systems for classifying oculocutaneous albinism. In general, these systems contrasted types of albinism having almost no pigmentation with types having slight pigmentation. In less pigmented types of albinism, hair and skin are cream-colored and vision is often in the range of 20/200. In types with slight pigmentation, hair appears more yellow or red-tinged and vision may be better. Early descriptions of albinism called these main categories of albinism “complete” and “incomplete” albinism. Later researchers used a test that involved plucking a hair root and seeing if it would make pigment in a test tube. This test separated “ty-neg” (no pigment) from “ty-pos” (some pigment). Further research showed that this test was inconsistent and added little information to the clinical exam.
Recent research has used analysis of DNA, the chemical that encodes genetic information, to arrive at a more precise classification system for albinism. Four forms of OCA are now recognized – OCA1, OCA2, OCA3 and OCA4; some are further divided into subtypes.

• Oculocutaneous albinism type 1 (OCA1 or tyrosinase-related albinism) results from a genetic defect in an enzyme called tyrosinase (hence ‘ty’ above). This enzyme helps the body to change the amino acid tyrosine into pigment. (An amino acid is a “building block” of protein.) There are two subtypes of OCA1. In OCA1A, the enzyme is inactive and no melanin is produced, leading to white hair and very light skin. In OCA1B, the enzyme is minimally active and a small amount of melanin is produced, leading to hair that may darken to blond, yellow/orange or even light brown, as well as slightly more pigment in the skin.
• Oculocutaneous albinism type 2 (OCA2 or P gene albinism) results from a genetic defect in the P protein that helps the tyrosinase enzyme to function. Individuals with OCA2 make a minimal amount of melanin pigment and can have hair color ranging from very light blond to brown.
• Oculocutaneous albinism type 3 (OCA3) is rarely described and results from a genetic defect in TYRP1, a protein related to tyrosinase. Individuals with OCA3 can have substantial pigment.
• Oculocutaneous albinism type 4 (OCA4) results from a genetic defect in the SLC45A2 protein that helps the tyrosinase enzyme to function. Individuals with OCA4 make a minimal amount of melanin pigment similar to persons with OCA2.

Researchers have also identified several other genes that result in albinism with other features. One group of these includes at least eight genes leading to Hermansky-Pudlak Syndrome (HPS). In addition to albinism, HPS is associated with bleeding problems and bruising. Some forms are also associated with lung and bowel disease. HPS is a less common form of albinism but should be suspected if a person with albinism shows unusual bruising or bleeding.

Morning Brain Spillage: Albinism

When Makayla was three months old, and her pediatrician diagnosed her with nystagmus, one of the first things they asked me was if it was possible that she was albino.  I laughed and just said that she took after me, thinking to myself, "can they not see how light I am?" 

My own dad (who is very dark in his skin, hair, and eyes) and I joked when I was a kid, that my mom's family was albino and that's why they, and I, were so, so, so pale (I actually REALLY hate the term pale, I prefer fair.  Pale sounds sickly, fair is just really light.).  But it was a joke!  I already knew that nystagmus was common in people with albinism, but obviously the doctors were just jumping to conclusions, because my daughter has all the same coloring as me (my eyes are green now, but were blue through elementary school and started changing in 7th grade), and I could not possibly be albino, since my eyes are green, and I have freckles, and although none of my friends would call it a tan, my skin tone does change some, when I get sun.  Although, my hair was white as a baby, whiter than Makayla's, it's now a very dark blonde, maybe even a light brown.  Obviously, I can't be albino.

But with more and more doctors asking about Makayla being albino, and now with her ocular albinism diagnosis, I'm learning so much more about albinism.  You might think of Powder or Whitey from Me, My Self & Irene when you think of someone with albinism, with the red or blue eyes, and the white hair and the translucent skin.  In fact, there are many different types of albinism and some include having some levels of pigment.  Now knowing this, I've asked doctors, if Makayla is albino, is it possible I am too?  But I'm always shut down, told that since my eyes are fine, I can't be albino, and that if I were the one with albinism that it would have been passed down to Austin, not Makayla (There is a dominant gene carried by mothers and passed down to sons, without the father having to carry a recessive gene, because Makayla is effected, and not Austin, we know this is not the case for us).

The more I read, I'm realizing that just may not be true. It really is frustrating how much information doctors just blurt out without really knowing for sure.

I was catching up on my friend Amy's blog, Through the Eyes of Liam, and was reading a post she has on Oculocutaneous Albinism.  In the post, she lists characteristics of the most common types of albinism, and I couldn't help but notice that this part, aside from the vision problems, describes me to a T:

OCA1b- A quick rundown:

White or light yellow hair at birth but darkens with age, can change to a golden or light brown

Skin remains white but often has some generalized pigmentation

Tans with sun exposure

Iris color remains blue or change to a hazel/green or brown/tan

Transillumination shows in streaks or clumps of pigment in the iris

Fine granular pigment may develop over time in the retina

Visual acuity is usually between 20/100 and 20/200 but can be as good as 20/60

Nystagmus and Strabismus is possible.

Involves tyrosinase enzyme--which converts tyrosine (an amino acid) into melanin

There are many other types of albinism, so I have to wonder if there is one that would include the first half of this description, but leaves out the part about transillumination, or maybe the transillumination improves with age, because I remember being a lot more sensitive to light as a child than I am now. I remember my eyes aching when I stepped outside some mornings.  I am just so curious...  In a lot of ways it would make so much sense, like how my dad ca be so dark, but I'm so fair, and how I don't exactly tan in the sun, I turn a sort of pink color.  It's not the same as a burn, but it's definitely not a a brown tan color.

I'm not sure what any of this actually means.  It doesn't change my life in anyway, and it doesn't change the way we go about treating Makayla, but it sure is facinating to think that you can go 30 years and not know something to significant about your self.  Regardless if I am albino or not, I probably at least carry the recessive gene, and my husband must also, in order for us to have passed it on to Makayla.

We are still waiting for the referral for genetic testing to come through.  Our pediatrician has sent a request to Stanford, but they are so backed up with referrals we don't expect to hear from them until November and then probably wont have an appointment until early next year.  That is just to see a geneticist and find out if our insurance will cover testing, which we don't think it does.  Besides wanting to know to quiet my own curiosity, finding out will help us to learn how likely we would be to have more children with albinism, and how likely Makayla and Austin are to have children with albinism.

VEPs And Stuff

Oh bloggy, blog, blog.  Did you miss me?  It's been too long!  Having this blog has not only helped me to connect with amazing moms of children with nystagmus and ocular albinism, but it helps me feel like I'm partaking in adult conversation when I'm locked in the house with toddlers for 12+ hours a day.  There is only so much, "ew, stinky poopies!" a thoughtful and intelligent person can take!  But...over the past two weeks, our normal routine was shaken up by a new, almost non-existent nap schedule, and I'm having a hard time figuring out where blogging fits back in. 

Today, we spent all of our morning and most of the early afternoon out of the house, so they are pretty happy to be home and chasing after the dog, for now.  And so, I write!

What took all morning was a visit to UC Berkeley.  Almost a year ago, Makayla's vision therapist helped us get into a research study at UC Berkley, in which they are studying how children with visual impairments learn about, and understand, the world around them.  For our participation in the study, the optometrist overseeing the study provides annual eye exams.

Makayla had her first when she was 9 months old, and we learned that she has only a very slight astigmatism, and that at that point glasses would not be beneficial.  The optometrist also preformed a VEP during that visit, which Dr. Hertle was able to use, since Makayla did not cooperate in Ohio.  The optometrist also predicted that, as her nystagmus improves (as it often does up until age 6), her vision may improve to be as good as 20/50 or 20/40.  To give an idea of how good that is, my "bad eye" was 20/40 at my last eye appointment, thanks to astigmatism, but I can still drive without any required correction.

Today, I got to share with the optometrist all about our trip to Ohio, and that we'll be going back soon for surgery.  I also shared with her that Dr. Hertle diagnosed her with a very mild form or ocular albinism.  She was very excited to hear all the news and updates on Makayla but had her doubts about the ocular albinism diagnosis...  She said that Makayla's ability to see contrast has greatly improved and that she is in the normal range for kids her age.  She said that the VEP test showed that Makayla sees quite well, but noted a new nearsightedness.  Part of Dr. Hertle's after surgery plan is to get Makayla in contacts as early as possible to help with light sensitivity and to slow her nystagmus, but since she now has a nearsightedness the optometrist predicts that by the time she is in the contacts, she will likely need a prescription.

We also did a new VEP test today, which Makayla was very cooperative and happy throughout.  The VEP test is a strange looking test where they put several leads on Makayla's head for measuring her brain waves, as she watches a monitor with various moving and flickering lines.  The optometrist explained that they are measuring her brain's response to various details and contrasts in the lines to determine how well she sees. They did the test with both eyes, then just with the left eye (since the left eye is currently dilated in preparation for her upcoming surgery), then they did both eyes at a further distance.  They will be sending the results of the exam and the VEP test to Dr. Hertle before her surgery.

The optometrist says that Makayla sees very well.  She said that her vision is "reduced by 2".  Normal would be 0 and she explained that most the kids she sees with nystagmus and ocular albinism are reduced by 6 to 10.  That being said, her depth perception will likely always remain very poor and she will always be sensitive to light, and obviously both of these things will effect her vision outdoors and in new places.  The surgery that Dr. Hertle will be doing will still help her vision.